RESUMO
A new type of absorption-powered artificial muscle provides high performance without needing a temperature change. These muscles, comprising coiled carbon nanotube fibers infiltrated with silicone rubber, can contract up to 50% to generate up to 1.2 kJ kg(-1) . The drive mechanism for actuation is the rubber swelling during exposure to a nonpolar solvent. Theoretical energy efficiency conversion can be as high as 16%.
Assuntos
Materiais Biomiméticos/química , Músculo Esquelético/química , Nanofibras/química , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Elastômeros de Silicone/química , Absorção Fisico-Química , Animais , Módulo de Elasticidade , Transferência de Energia , Humanos , Teste de Materiais , Nanoconjugados/química , Nanoconjugados/ultraestrutura , Nanofibras/ultraestrutura , Estresse MecânicoRESUMO
The fabrication and characterization of highly flexible textiles are reported. These textiles can harvest thermal energy from temperature gradients in the desirable through-thickness direction. The tiger yarns containing n- and p-type segments are woven to provide textiles containing n-p junctions. A high power output of up to 8.6 W m(-2) is obtained for a temperature difference of 200 °C.
RESUMO
Magnesium-diboride-coated carbon nanotube arrays are synthesized by templating carbon-nanotube aerogel sheets with boron and then converting the boron to MgB2. The resultant MgB2-CNT sheets are twisted into flexible, light-weight yarns that have a superconducting transition around 37.8 K and critical current and critical field comparable with those of existing MgB2 wires, but have about 20 times lower density than bulk MgB2.